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目的：对新疆奎屯地方性砷中毒病区水样中的砷进行价态分析，研究砷中毒的发病机理。方法：采用新银盐光度法，用硼氢化钠（ＮａＢＨ４）作还原剂，先在醋酸醋酸钠缓冲溶液（ｐＨ５．２）中将Ａｓ（Ⅲ）转化为ＡｓＨ３，加入盐酸将样品溶液调至ｐＨ≤１，继续将Ａｓ（Ⅴ）转化为ＡｓＨ３，分别被硝酸硝酸银聚乙烯醇乙醇混合液显色。结果：实现了连续分步测定Ａｓ（Ⅲ）和Ａｓ（Ⅴ），检测限为００１５μｇ。应用此法测得新疆奎屯砷中毒病区深井水中Ａｓ（Ⅲ）和Ａｓ（Ⅴ）含量，其中Ａｓ（Ⅲ）的含量为１０％，Ａｓ（Ⅴ）的含量为９０％。结论：新银盐光度法测Ａｓ（Ⅲ）和Ａｓ（Ⅴ）含量，相对标准偏差在４％以内，回收率为９４％～１０４％，具有较高的精密度和准确度。
Objective: To analyze the valence state of arsenic in water of endemic arsenism in Kuitun, Xinjiang, and to study the pathogenesis of arsenism. Methods: As (Ⅲ) was converted to AsH3 in sodium acetate-sodium acetate buffer solution (pH5.2) with sodium borohydride (NaBH4) as a reducing agent by the new silver salt photometry. The sample solution was adjusted to pH≤1, continue As (Ⅴ) into AsH3, were nitric acid silver nitrate polyvinyl alcohol ethanol mixture color. Results: As (Ⅲ) and As (Ⅴ) were achieved in a sequential stepwise manner with a detection limit of 0015 μg. The As (Ⅲ) and As (Ⅴ) contents in deep well water of Kuitun arsenism in Xinjiang were measured by this method. The As (Ⅲ) content was 10% and the As (Ⅴ) content was 90%. Conclusion: As (Ⅲ) and As (Ⅴ) contents of As (Ⅲ) and As (Ⅴ) were determined by spectrophotometry. The relative standard deviations were less than 4% and the recoveries were 94% -104%. The results showed that the method has high precision and accuracy.